In recent years, a type of mobile communications network known as an “ad-hoc” network has been developed. In this type of network, each mobile node is capable of operating as a base station or router for the other mobile nodes, thus eliminating the need for a fixed infrastructure of base stations. As can be appreciated by one skilled in the art, network nodes transmit and receive data packet communications in a multiplexed format, such as time-division multiple access (TDMA) format, code-division multiple access (CDMA) format, or frequency-division multiple access (FDMA) format.
More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in a conventional ad-hoc network, further enable the mobile nodes to access a fixed network and thus communicate with other mobile nodes, such as those on the public switched telephone network (PSTN), and on other networks such as the Internet. Details of these advanced types of ad-hoc networks are described in U.S. patent application Publication No. US-2002-0058502-A1 entitled “Ad Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networks”, filed on Jun. 29, 2001, in U.S. Pat. No. 6,807,165 entitled “Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel”, granted Oct. 19, 2004, and in U.S. Pat. No. 6,873,839 entitled “Prioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access System”, granted Mar. 29, 2005, now, the entire content of each being incorporated herein by reference.
As can be appreciated by one of ordinary skill in the art, the capacity of multihopping wireless networks diminishes as the number of nodes increases in the network, for example as described in a document by P. Gupta and P. R. Kumar entitled “The Capacity of Wireless Networks,” IEEE Transactions on Information Theory, Issue 2, March 2000. In order to increase the capacity of multihopping wireless networks, fixed infrastructure nodes can be introduced as described, for example, in the document by P. Gupta and P. R. Kumar, referenced above, and in a document by M. J. Miller, W. D. List and N. H. Vaidya entitled “A Hybrid Network Implementation to Extend Infrastructure Reach,” Technical Report, January 2003. These infrastructure nodes extend the network coverage, provide mobile nodes access to the global Internet, and become the aggregate points for the traffic to and from different mobile nodes. Hence, these infrastructure nodes can become the bottleneck points in the network.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.